The present invention relates to a suction device for removing X-ray sheet films from one of several dispenser magazines of an X-ray sheet film cassette loading and unloading apparatus.
An X-ray sheet film cassette loading and unloading apparatus which is provided with a suction device is disclosed for example in the German Patent 3,610,660. In this device a suction element is arranged on an angular lever. The angular lever is supported rotatably about an axis which extends parallel to the upper surface side or to a front edge of an X-ray sheet film stack and is fixably connected with a base plate. Furthermore, the angular plate engages the pin or a spring with a toothed segment which is also rotatable about an axis of the angular lever. The toothed segment engages with the toothed wheel mounted on a shaft of a motor. The motor for moving the suction element is fixedly arranged on the base plate.
A spring-biased pin is arranged on the base plate and in particular on its end which faces toward the X-ray sheet film stack. During placing of the suction device on an X-ray sheet film stack, the pin is displaced against the force of the spring element. This displacement is detected by means of a proximity or microswitch and blocks the placing movement of the suction device. The suction element now lies on the uppermost sheet film of the X-ray sheet film stack and holds it by suction by means of a vacuum pump. After this holding by suction, the motor is activated and the suction member is turned by 90.degree. by means of the toothed gear and toothed segment and the sheet film is pressed against the suction member by a pressing plate. The X-ray sheet film adhered by suction is bent around a point in which the pin abuts. The bending radius approximately corresponds to the length of the angular lever. When the X-ray sheet film adheres by suction and is bent, the suction device in which the base plate is connected with the transporting device is moved away of the X-ray sheet film stack. The above described suction device in accordance with the prior art has the disadvantage that the bending radius during rolling of the X-ray sheet film cassette from the task is relatively great and therefore with a predetermined film stiffness the tendency for peeling off of a film which adheres to the sucked film is relatively low. In addition, during the rolling of the sheet film from the stack, the film is pressed against the stack at the point where the pin abuts, and a transporting movement of the suction device is first released when the turning movement of the suction member is finished. Therefore no continuous rolling-off or releasing movement of the X-ray sheet film from the X-ray sheet film stack is produced.